The present invention relates to switch networks, and more particularly, the present invention relates to a method for determining a signal path to avoid failed devices in a switch network.
Typical communication satellites contain networks of traveling wave tube amplifiers (TWTA""s) that consists of many active devices and backup devices. Should a TWTA fail, a backup is activated. The signal is re-routed around the failed device through switches. In the past, TWTA networks were small and relatively simple to design and analyze. However, today""s communication satellites are equipped with larger TWTA networks, increasing the complexity of the payload.
Presently, the method of determining the switch states during a TWTA failure involves manually finding a re-route path. For smaller and simpler TWTA networks, the task is tedious, but relatively easy. For more complex TWTA networks, the task becomes time consuming and, due to the volume of switches and TWTA""s, is prone to human error.
In the brute force method, the search involves checking all the possible states for all of the switches. The brute force method used to re-route signals is tedious. For example, in a typical xe2x80x9cRxe2x80x9d-switch network, each switch has three possible states. There may be fifty or more switches in the network. This translates into 350 or 7xc3x971023 possible states. If 1 micro-second of processing time per state is allowed, it would take approximately 22 billion years to process a 50 switch ring on a typical computer.
The use of xe2x80x9cRxe2x80x9d-switches also limits the network""s capabilities. For example, xe2x80x9cRxe2x80x9d-switch networks cannot recover multiple consecutive TWTA failures. New switches, such as xe2x80x9cMxe2x80x9d-switches, are more complex, but they can accommodate multiple consecutive TWTA failures. Unlike xe2x80x9cRxe2x80x9d swtiches, xe2x80x9cMxe2x80x9d switches consist of six individual ports, allowing interconnections that are more complex and functional. Thus using the traditional method of analyzing switch paths becomes overwhelming with a more complicated switch limiting their use.
An improved method of analyzing a switch network will allow more complex switching networks to be employed which could potentially result in weight reductions for spacecraft applications. Also, the time required to design a network could be significantly reduced.
The method of the present invention finds re-routing path solutions for signals within a switch network. The path solutions can be subject to special constraints that provide the most desired solution. The method applies an algorithm that works by transforming a global problem into many individual sub-problems. It then solves the individual subproblems systematically according to desired constraints until the global solution is met. In other words, the algorithm finds a unique state for each switch such that the overall requirements of the system are met.
It is an object of the present invention to increase the reliability of a TWTA network by using more advanced switches without compromising design cycle time. It is another object of the present invention to determine a re-routed signal path to avoid a failed device.
It is a further object of the present invention to break a global problem into many individual problems that can be solved individually until a solution to the global problem is found. It is still a further object of the present invention to apply local constraints to each individual problem until global constraints are satisfied.